Hot-blast stove.



NITE STATES ATENT OFFICE,

HOT-BLAST STOVE.

SPECIFICATION formirg part of Letters Patent No. 642,924, dated February6, 1900.

Application filed November '7, 1899. Serial No. '736,091. (No model.)

To all whom it may conccrn:

Be it known that I, FRANK C. ROBERTS, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia, State ofPennsylvania, have invented a new and useful Improvement in I-Iot-BlastStoves, of which the following, taken in connection With theaccompanyingdrawings, is a full and clear specification.

My invention relates to improvements in hot-blast stoves whereby theloss of heat by radiation is reduced and at the same time a morethorough combustion of the gases secured.

Figure 1 is a vertical section through a hotblast stove 5 Fig. 2, ahorizontal section online A B, (see Fig. 1,) and Fig. 3 a horizontalsection on line C D. (See Fig. 1.)

Similar letters reter to similar parts throughout the several views.

As ordinarily constructed fire-brick stoves of the type illustrated arebuilt with a solid wall between the combustion-chamber and the outsideof the stove. As this wall becomes hot by the burning of gas in thecombustionchamber there is a certain amount of heat lost through thewall by radiation, &e Again, as ordinarily constructed air for thecombustion of gas is admitted in the vicinity of the gas connection tothe stove, and while the combustion is good under these circumstancesyet it is much better when the air adnitted is heated.

The objects of ny invention are (a)`to prevent the loss of heat referredto above and (b) to heat a portion of the air for the combustion of thegases and deliver it into the combustion-chamber at a desirable point.

The drawings illustrate a fire-brick stove, WhereinN is the metal shell;E, the combustion chamber; F, the Checker-work, supported by piers G; Hand I, walls around the combustion-chamber, between which is space J,open at bottom to atm osphere by openings K, controlled by valves, andopen at top to combustion-chamber by openings L.

The operation of my invention is as follows: Gas is admitted through theopening M, controlled by a valve. This gas is partially consumed by theadmission of air in the vicinity of M, the quantity of air beingcontrolled by a gate or other type of valve. The products of combustionpass upward through E, downward through F, and out of the stove by thechimney connection O. Air is also admitted through openingsK to space Jand in passing upward absorbs the heat passing through wall H, beingfinally delivered in a heated state into the combustion-chamberE throughopenin gs L, where it comes in contact with the partially-consumed gasesand contributes toward their thorough combustion. By the abovedescribedprocess the exterior wall I is prevented from reachin g a hightemperature, and thus the loss of heat is prevented, while the heatwhich would otherwise be wasted is delivered at the top of thecombustion-chamber.

The type of stove shown in the drawings is known as a two-pass stove,having its combustion -chanber next the outer walls. A stove may beeither two-pass, three-pass, or any number of passes and yet have thecombustionchamber located next the outer walls, as shown in thedrawings.

I do not limit my invention to the type of stove shown in the drawings.It may be applied to any type of stove, provided only that thecombustion-chamber is located next the outer walls in distinction from astove in which the combustion-chamber is surrounded on all sides byChecker-work.

Having fully described my invention, what I claim, and desire to coverby Letters Patent, 1s--` In a hot-blast stove having itscombustionchamber located next the outer walls, the combination of acombustion-chambe'r, two walls between the combustion-chamber and the eXternal metal shell, an air-space between said two walls, openingscontrolled by Valves or other devices leading from the atmosphere -intosaid air-space and openings from said air-space into thecombustion-chamber.

In testimony whereof I have hereunto set my hand this &th day ofNovember, 1899.

FRANK C. ROBERTS.

Witnesses:

I. G. BAYLEY, C. A. ANDERSON.

